A study performed at LDS Hospital, found that a single, whole-leg compression ultrasound could safely exclude the diagnosis of suspected, symptomatic, first-episode deep vein thrombosis of the leg. A subsequent metanalysis of studies of the same technique confirmed this finding, but observed that the utility of this strategy in pregnant patients required further study, as only 57 of the over 4,500 subjects in the pooled metanalysis were pregnant.